Device and method for continuously inspecting containers

ABSTRACT

The present invention provides an inspection device for continuously inspecting supplied containers, in particular bottles, comprising a feed conveying apparatus, which may be embodied to supply containers to the inspection device in succession, and which may include one or more of at least one inspection apparatus, which is embodied to inspect the supplied containers, a discharge conveying apparatus, which is embodied to discharge the inspected containers, and a throughput station for the containers, arranged between the feed conveying apparatus and the discharge conveying apparatus, wherein the throughput station has a transportation apparatus with an individual drive and a plurality of conveying means movable by means of the individual drive in an individual manner and independently from one another, said transportation apparatus being embodied to convey the containers from the feed conveying apparatus to the discharge conveying apparatus.

CROSS OF REFERENCE TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 15/534,422 entitled “DEVICE AND METHOD FOR CONTINUOUSLY INSPECTINGCONTAINERS,” filed on Jun. 8, 2017. U.S. patent application Ser. No.15/534,422 claims priority to U.S. National Phase of InternationalPatent Application Serial No. PCT/EP2015/073351, entitled “DEVICE ANDMETHOD FOR CONTINUOUSLY INSPECTING CONTAINERS,” filed on Oct. 9, 2015.International Patent Application Serial No. PCT/EP2015/073351 claimspriority to German Patent Application No. 10 2014 226 965.2, filed onDec. 23, 2014. The entire contents of each of the above-citedapplications are hereby incorporated by reference it their entirety forall purposes.

FIELD OF THE INVENTION

The present invention relates to a device and a method for continuouslyinspecting containers, in particular bottles, e.g. for emptiesinspection in the beverage industry.

PRIOR ART

Inspection machines are used e.g. in the beverage industry for examiningempties, such as glass or plastic bottles, for damage, contamination orresidues of liquid before the examined containers are returned to theproduct cycle. In so doing, the containers to be inspected must beguided, at least temporarily, such that the bottom area and the outletarea are freely accessible simultaneously. This allows inspection bytransmitted light in the direction of the main axis of the container,whereby e.g. the container bottom can be inspected with respect todamage or a residue of liquid contained in the container can be detectedby infrared. Inspection is here normally carried out in a fullyautomatic manner with the aid of suitable optical systems, e.g. bymaking use of a camera and an LED flash lamp, and with the aid of asuitable evaluation software, which draws conclusions from themeasurement data and image data, respectively, with respect to theabove-mentioned damage and contamination. Damaged and/or contaminatedcontainers can then be discharged automatically and subjected to furtherprocessing and/or cleaning.

Linear inspection machines known from the prior art comprise athroughput station within which the containers are linearly conveyed bypressure applied from both sides via conveyor belts arranged on bothsides. Since the containers are laterally held in the throughputstation, the bottom area and the outlet area of the containers arefreely accessible at the same time. An inspection machine comprising aconveyor belt in the area of the throughput station is known e.g. fromEP 0 415 154 B1. The conveyor belts do not have defined positions forholding the containers, but they are able to pick up containers atarbitrary positions. A plurality of containers which are simultaneouslypresent in the throughput station are here conveyed synchronously by theconveyor belts. Typically, rotationally symmetrical containers, such asbottles, are rotated by 90° about their container axis along the transitroute, so that sidewall inspection units provided in the infeed anddischarge areas of the inspection machine will be able to inspectrespective different areas of the circumferential surface of thecontainers.

In the case of the inspection machines with belt conveyance in thethroughput station known from the prior art, the containers must be fedpressureless, i.e. without being in contact with one another, in thecontainer infeed. This necessitates the use of a complex and bulkydevice for pressure reduction, i.e. for spatially separating thecontainers that are normally conveyed in a mutually abutting mode, inthe incoming container flow, e.g. by providing transfer elements,sawtooth star wheels or infeed worms. The frequently used transferelements are not able to define a defined minimum distance so thatsegment-type discharge elements cannot be used. In addition, containerrotation during conveyance by means of conveyor belts often has theeffect that the containers tilt by a few degrees in the direction ofmovement, in particular if the holding area deviates from the idealcylinder shape. This may impair the efficiency of inspections, e.g. forthe container bottom or for screw threads, and guiding of the containerson the discharge side may become more difficult in the case of highercontainer throughput rates of the inspection machine.

Hence, it is the object of the present invention to provide a device anda method for continuously inspecting containers, which avoid theabove-mentioned drawbacks. In particular, feeding the containers to anddischarging them from the inspection machine is to be simplified.Furthermore, the conveying stability of the containers in the throughputstation is to be increased so as to improve the efficiency of theinspection units. In addition, it is the object of the present inventionto facilitate, in the case of the inspection machine used, a change ofthe type of containers.

DESCRIPTION OF THE INVENTION

The above-mentioned objects are achieved by an inspection device forcontinuously inspecting fed containers, in particular bottles,comprising: a feed conveying device configured to feed containers to theinspection device in succession, at least one inspection unit configuredto inspect the fed containers, a discharge conveying device configuredto discharge the inspected containers, and a throughput station for thecontainers, which is arranged between the feed conveying device and thedischarge conveying device, the throughput station comprising a conveyorarrangement with an individual drive and a plurality of conveying units,which are movable by means of the individual drive individually andindependently of one another, the conveyor arrangement being configuredto convey the containers from the feed conveying device to the dischargeconveying device.

The containers may be cans, glass bottles or other glass containershaving a lid, plastic bottles, consisting e.g. of PET, or the like. Inparticular transparent containers, such as glass bottles or plasticbottles made of PET, can be inspected in an advantageous manner by theinspection device, since in the case of transparent objects not only theside facing the respective sensor or the respective camera but also theopposite side of the container can be detected and examined. On thebasis of the sidewall inspection units described hereinafter, the wholecircumferential surface of the container can thus be inspected byrotating the container in the throughput station.

According to the present invention, the inspection device comprises afeed conveying device for feeding the containers in succession, adischarge conveying device for discharging the inspected containers, anda throughput station for the containers, which is arranged between thefeed conveying device and the discharge conveying device. Forcontinuously inspecting the containers, the inspection device has fedthereto a flow of containers via the feed conveying device, thecontainers of said flow of containers being then conveyed by means ofthe conveyor arrangement described hereinafter along a conveying routeconnecting the feed conveying device to the discharge conveying device,whereupon they are discharged by the discharge conveying device. Withinthe throughput station, the containers are conveyed such that the bottomarea and the outlet or top area of the conveyed containers are freelyaccessible at the same time. The feed conveying device and/or thedischarge conveying device may be configured e.g. as conveyor beltsconveying the containers under pressure, i.e. in a mutually abuttingmode. Alternatively, also other conveying systems may be used, includingthe linear motor drives described hereinafter, but belt conveyance orinfeed star wheels and/or discharge star wheels are imaginable as well.The systems referred to are sufficiently known in the prior art and willtherefore not be explained in detail in the present context. Referenceshould only be made to the fact that the above-mentioned conveyorarrangement of the throughput station takes over the fed containers fromthe feed conveying device and transfers them to the discharge conveyingdevice after conveyance through the throughput station. To this end, thecontainers, which are conveyed e.g. in an upright condition by the feedconveying device, can be taken off from a conveyor belt and raised, sothat their bottom surface will become accessible for inspection. Theconveyor arrangement may then put down the inspected containers on aconveyor belt of the discharge conveying device.

According to the present invention, the inspection device comprises atleast one inspection unit for inspecting the fed containers. Said atleast one inspection unit may be arranged in the area of the throughputstation on the conveying route of the conveyor arrangement, on the feedconveying device or also on the discharge conveying device. In the areaof the throughput station, e.g. an inspection unit for sealing surfaceinspection may be provided, which inspects an outlet area of thecontainers for damage by means of an illumination unit and a camera,e.g. a CCD camera. Alternatively or additionally, an inspection unit forliquid residue inspection, e.g. by means of high frequency and/orinfrared, may be provided. As has already been mentioned, it isespecially possible to provide an inspection unit for inspecting thecontainer bottom, in the case of which a camera records an image of thecontainer bottom, which is illuminated by an LED flash lamp. It is alsoimaginable to provide an inspection unit for inner sidewall inspection,in the case of which the interior of the container is inspected throughthe container outlet by means of a CCD camera. Other examples areinspection units for thread inspection or lateral outlet inspection,which inspect the outlet area of the containers. It goes without sayingthat the above-mentioned inspection units may have added thereto, or maybe replaced by, other container inspection units known in the prior art.

In addition, the inspection units for sidewall inspection described inmore detail hereinafter can be provided at the feed conveying deviceand/or the discharge conveying device. Furthermore, the feed conveyingdevice may have provided thereat an inspection unit for foreigncontainer detection by means of which foreign containers can be detectedand discharged prior to entering the throughput station. The inspectionunits described execute the respective inspection steps in an at leastpartially automatic manner by detecting each container of the continuousflow of containers in the respective container area making use ofsensors or of optical units. The detected sensor or image data can,moreover, be processed in a fully automatic manner, and detecteddefective containers can be discharged downstream of the inspectiondevice.

According to the present invention, the containers are conveyed alongthe conveying route of the conveyor arrangement of the throughputstation by means of an individual drive and a plurality of conveyingunits, which are movable by means of the individual drive individuallyand independently of one another. The term individual drive describeshere and in the following a drive that drives the plurality of conveyingunits individually. The drive may be provided as part of the respectiveconveying unit and/or as a separate drive, which is configured such thatthe conveying units are movable individually and independently of oneanother. This independent movement relates to the position as well as tothe speed of the conveying unit. The conveyor arrangement is providedwith a plurality of individually movable conveying units. The conveyingunits are configured such that they are able to convey one or aplurality of containers along the conveying route with an individualdisplacement-time profile. In particular, the conveying units may beconfigured as carriages or runners, each of them provided with holdingdevices for conveying the containers. The individual drive may inparticular be the linear motor drive, which will be described in moredetail hereinafter and in the case of which the conveying units aremoved individually and independently of one another via magneticinteraction with one or a plurality of linear stators. For defining therespective displacement-time profiles of the conveying units and thus ofthe conveyed containers, the inspection device according to the presentinvention may comprise an open-loop and/or closed-loop control unit aspart of the conveyor arrangement, said open-loop and/or closed-loopcontrol unit controlling the conveying units and/or the individual drivein a suitable manner. The number of conveying units may be chosen inaccordance with the desired throughput of containers of the inspectiondevice as well as depending on a length of the conveying route and ofthe conveyor tracks referred to hereinafter. Normally, the number ofconveying units provided is at least large enough for allowing thenecessary inspection steps to be carried out at the possibly more thanone inspection unit preferably at a plurality of containers in parallel,and for preventing gaps in the continuous inspection.

According to a further development, the conveyor arrangement maycomprise a first conveyor track having movably arranged thereon a firstplurality of conveying units, and a second conveyor track having movablyarranged on a second plurality of conveying units, said first conveyortrack and said second conveyor track being arranged relative to oneanother and relative to the feed conveying device and the dischargeconveying device such that, in the area of the throughput station, pairsof oppositely engaging conveying units for the containers can be formed,said pairs consisting each of a conveying unit of the first plurality ofconveying units and of a conveying unit of the second plurality ofconveying units.

The first and the second conveyor track may here extend beyond the areaof the conveying route in the area of the throughput station. The firstand second conveyor tracks may, in principle, have an arbitrary shape aslong as a part of the two conveyor tracks is arranged between the feedconveying device and the discharge conveying device such that containerscan be conveyed from the feed conveying device through the throughputstation to the discharge conveying device. In particular, the conveyortracks may be substantially closed, substantially closed meaning herethat the respective conveyor track comprises at least one closed pathfor the respective plurality of conveying units. This may e.g. berealized by providing a feedback track as part of the conveyor track,said feedback track allowing the conveying units to be returned to thefeed conveying device after transfer of the containers to the dischargeconveying device. Each conveyor track may, however, also be configuredsuch that it is partially open in such a way that at least a subsectionof the conveyor track is configured as a dead end for bufferingconveying units. Moreover, it is not necessary that the whole conveyortrack in question is provided with the described individual drive forthe conveying units. Alternatively, the part of the conveyor trackoutside the throughput station and, in particular, the feedback trackmay be provided with a continuous drive, such as a conveyor belt or thelike.

The number of the conveying units movably arranged on the respectiveconveyor track depends on the number of containers to be conveyedsimultaneously, i.e. on a predetermined throughput of containers pertime interval for the inspection device. The number of conveying unitsarranged on the first conveyor track may especially correspond to thenumber of conveying units arranged on the second conveyor track, or, ifnecessary, it may differ therefrom.

According to this further development, the first and second conveyortracks are arranged relative to one another and relative to the feedconveying device and the discharge conveying device such that, in thearea of the throughput station, pairs of oppositely engaging conveyingunits for the containers can be formed, said pairs consisting each of aconveying unit of the first plurality of conveying units and of aconveying unit of the second plurality of conveying units. Inparticular, the first and second conveyor tracks are arranged such thatthe pairs of conveying units are formed at the beginning of theconveying route of the throughput station for taking up the containersfrom the feed conveying device, said pairs being maintained along thewhole conveying route and de-established only at the end of theconveying route for transferring the containers to the dischargeconveying device. The pairs are here formed and de-established in thatthe two conveyor tracks approach one another and diverge from oneanother at the locations in question.

The phrase forming a pair of conveying units should be understood hereand in the following such that the two conveying units forming therespective pair are, by means of the individual drive and an open-loopand/or closed-loop control unit, positioned and moved along therespective conveyor track such that a pair is obtained through thespatial position of the conveying units relative to one another andrelative to the conveying route. In particular, no mechanical couplingof the oppositely engaging conveying units will normally be necessaryfor forming the pairs.

The phrase oppositely engaging conveying units stands here for conveyingunits which are configured and oriented such that the containers can beconveyed between oppositely engaging conveying units and by means ofmechanical contact with the latter such that the bottom area as well asthe outlet area of the containers are freely accessible duringconveyance. To this end, the conveying units act on a substantiallycylindrical part of the container during conveyance, substantiallycylindrical meaning that the cross-section of the container changes inthe area of mechanical contact with the conveying units only to such asmall extent that inspection of the container, e.g. of the containerbottom, will not be impaired by the conveying units engaging thecontainer. The conveying units are controllable such that successivecontainers can be conveyed with a predetermined spacing between them inthe conveying direction along a conveying route of the conveyorarrangement.

In particular, the oppositely engaging conveying units of each pair canbe moved simultaneously by means of an open-loop and/or closed-loopcontrol unit of the conveyor arrangement along the conveying route ofthe throughput station such that a container located between a pair ofoppositely engaging conveying units will be carried along due to thesimultaneous movement of the conveying units. A simultaneous movement ofthe conveying units may here be realized by an arbitrary one of theembodiments of the conveying units described hereinafter and the drivesystem of said conveying units. In addition, the conveying route may bestraight or curved, also at least partially curved, depending on theconfiguration and mode of transfer of the containers at and from thefeed conveying device and the discharge conveying device, respectively.

Conveyance of the containers along the conveying route of the throughputstation by moving simultaneously pairs of oppositely engaging conveyingunits allows reliable holding and guiding of the respective container,in particular also without the container resting on a conveying surface.Provided that the conveying units have a suitable structural design (seebelow), such reliable holding and guiding is made possible for a largenumber of different containers, in particular containers with differentcross-sectional areas and diameters, without any changeover of theconveying units or exchange of shaped parts.

The first conveyor track and the second conveyor track may be arrangedin parallel, in particular along the conveying route of the throughputstation. Such a parallel arrangement is also possible for curved piecesof the conveying route by arranging the first and the second conveyortracks at a constant distance from one another. The distance between thefirst and second conveyor tracks may here be predetermined on the basisof the structural design of the conveying units and the maximum diameteras well as the cross-sectional shape of the containers to be conveyed. Aparallel arrangement of the first and second conveyor tracks along theconveying route guarantees here that the carried-along container will beheld with a constant lateral force by the oppositely engaging conveyingunits throughout conveyance along the conveying route.

According to a further development, the conveying units may compriseholding devices, with oppositely engaging conveying units of a pairbeing oriented relative to one another in the area of the throughputstation such that at least one container can be held and conveyed in aform-fit or in a force-fit manner between holding devices of oppositeconveying units. The holding devices may e.g. be configured in the formof clamps, and said clamps may be configured such that they arepassively or actively controllable. In particular, clamps are imaginablethat are used for fixing a substantially cylindrical part of thecontainers in a form-fit or in a force-fit manner between clamps ofoppositely engaging conveying units, the container held being supportedsuch that it is rotatable about is longitudinal axis in the case ofform-fit fixing between the clamps. This can be accomplished e.g. byproviding rotatable rollers on the clamps. Said rollers may consist of amaterial exhibiting a sufficiently high static friction or they may becoated with such a material, so as to avoid slipping out of the conveyedcontainers. In addition, the holding devices may be configured in avertically adjustable manner so as to allow an easy grade change tocontainers having a different height. According to the presentinvention, the holding devices are arranged on the conveying units of apair such that they are disposed in opposed relationship with oneanother along the conveying route of the throughput station. Hence, acontainer to be conveyed can be fixed in position between the holdingdevices of such a pair and can be advanced by moving the conveying unitsof the pair simultaneously along the conveying route.

Holding the containers in a force-fit or in a form-fit manner by theoppositely engaging conveying units is also possible in cases where theinspection of the container makes neck handling impossible, as will bethe case e.g. when the inner sidewall is inspected. In addition, thepresent further development allows individual containers to be takenover from an infeed flow, in which the containers are conveyed under rampressure, i.e. in which the circumferences of the containers are incontact with one another along the conveying direction. When containersare fed under ram pressure, possible holding devices can normally noteasily be introduced between the containers so as to allow holding in aform-fit or in a force-fit manner. When oppositely engaging conveyingunits are used, such insertion between the containers will, however, notbe absolutely necessary for singling a container out of the containerflow for the purpose of conveyance through the throughput station. Dueto the laterally engaging holding devices and the lateral force appliedthereby, a small contact area, in comparison with the totalcircumference of the container, will already suffice for establishing aform-fit or a force-fit hold.

The clamps of the holding devices may, for example, be configured suchthat they act laterally on the containers. The ends of the clamps mayhave provided thereon a respective support roller so that the conveyedcontainer can deliberately be rotated by one or a plurality of frictionbelts acting thereon from the side, said friction belts being arrangedin the area of the throughput station. The holding devices mayadditionally be provided with a shear mechanism of the clamps, which mayhave spring type characteristics so as to compensate for tolerances ofthe container diameter. According to the above-mentioned furtherdevelopments, holding devices that are displaceable relative to theconveying unit can be advanced towards the container via a control curveand/or guidance of the conveying units along curved conveyor tracks.

The friction belt or the friction belts may be electrically driven. Thedrive of the friction belt(s) may be controlled via an open-loop and/orclosed-loop control unit such that the container will be rotated inaccordance with the container diameter so as to accomplish rotationthrough an angle between 70° and 110°, preferably through approximately90°. The rotation of the container can here be accomplished by afriction belt engaging from one side or by two friction belts engagingfrom both sides. As has already been mentioned, the rollers of theclamps may consist of a material having a sufficiently high staticfriction or may be coated with such a material, e.g. rubber, so that thecontainers can be held in a reliable manner.

A further embodiment used for rotating the container may be realizedafter the fashion of a ratchet mechanism, the rollers acting on thecontainer being provided with bearings on at least one side of thecontainer, said bearings locking in one direction of rotation. When thelinear drive is then controlled such that, during forward movement ofthe two conveying units acting on the container, one of the conveyingunits moves temporarily faster, so that there will be a difference ofe.g. up to 10 mm between the clamps in the direction of movement, arolling movement of the container through a small angle will take placedue to the relative displacement of the clamps acting thereon. When,subsequently, the speed of one of the conveying units is reduced, afreewheel unit will block reverse rotation of the support rollers, sothat the container will now be rotated by said angle. Subsequently, theconveying units are again at the initial position so that the processcan be repeated for gradually rotating the container. Hence, a mechanismsimilar to a ratchet is realized for deliberately rotating thecontainers. It goes without saying that the locking direction of therollers may also be provided such that the container will be rotatedwhen the conveying units are moved apart, whereas the rollers roll onthe container surface when the conveying units are again moved towardsone another. The relative movement of the conveying units can here becontrolled by an open-loop and/or closed-loop control unit of theconveyor arrangement.

According to a special embodiment, the holding devices may comprise oneor a plurality of Y-shaped clamps, i.e. the clamps comprise an angularelement which is defined by two legs and which is connected to alongitudinal element. The holding devices are arranged on the conveyingunits such that the opening of the angular element of the upsilon facesthe container to be conveyed. Each conveying unit may comprise one or aplurality of clamps arranged one on top of the other along thelongitudinal axis of the containers to be conveyed, a larger contactarea with the container to be conveyed resulting in a higher reliabilityof conveyance due to the higher friction. The number of clamps of theconveying units of the first plurality of conveying units may differfrom the number of clamps of the conveying units of the second pluralityof conveying units. In particular, it is imaginable that the clamps ofopposed conveying units interengage in a comblike fashion, but withoutany direct mechanical contact, so as to achieve holding with the highestdegree of stability, which will prevent the conveyed containers fromtilting. The size and shape of the Y-shaped clamps may be predetermineddepending on the cross-sectional shape and size of the containers to beconveyed. The use of Y-shaped clamps has the advantage that, due to theY-shape, a large number of cross-sectional radii can be fixed betweentwo oppositely engaging clamps. Hence, the inspection device accordingto the present invention allows a product change between containers ofdifferent cross-sections, without any exchange of shaped parts forconveyance in the throughput station. Possible set-up times can thus bereduced substantially.

According to a special further development, the angle between the Y-legsof the clamps, i.e. the angle of the angular elements, can be changedespecially by configuring at least the legs such that they consist of apermanently elastic material or by configuring them as angularlyadjustable legs having a resilient element arranged between the legs,and/or the holding devices may be arranged on the conveying units suchthat they are linearly and/or angularly displaceable. A permanentlyelastic material is here and in the following a material which isreversibly deformable and which counteracts the deformation by means ofa resetting force. By way of example, the Y-legs may consist of anelastic synthetic material, such as an elastomer, e.g. rubber or naturalrubber, or they may consist of suitably shaped sheet metal or metallicwebs, e.g. made of steel and e.g. in the form of a leaf spring. Itfollows that, by pressing the Y-legs of the clamp of the holding deviceonto the container to be conveyed, the angle between the Y-legs willchange, depending on the respective pressure applied, so that variouscontainers having a cross-sectional diameter within a rangepredetermined by the length of the Y-legs can be held in a form-fit andpossibly a force-fit manner.

In order to guarantee reliable holding of the containers to be conveyed,the clamps may additionally consist of a material having a highcoefficient of static friction or they may be coated with such amaterial on the contact side of the clamps. By way of example,elastomeric coatings may be used also in this case, said elastomericcoatings being able to adapt themselves to the shape of the containerwithin certain limits. The materials may here be selected in accordancewith the shape and the weight of the containers to be conveyed.

According to an alternative embodiment, the holding devices may beconfigured such that the Y-legs of the clamps enclose a right angle,i.e. they may be configured with right-angled angular elements. Aright-angled angular element allows, just as an angularly adjustableangular element, conveyance of containers, in particular circularcylindrical containers, of different cross-sectional sizes. Preferably,the legs of the angular element have a length that corresponds to theradius of the maximum container to be conveyed. Possible overlapping ofsuch legs of opposed clamps during conveyance of smaller containers canbe prevented by the above-mentioned comblike formation or by verticallyoffsetting the respective clamps.

As has been mentioned hereinbefore, the holding devices may be arrangedon the conveying units in a linearly displaceable manner. A lineardisplacement, in particular of the “long” Y-leg of the clamps of theholding devices, may be realized by means of suitable drive unitsarranged on the conveying units, such drive units being e.g.servomotors, hydraulic or pneumatic lifting cylinders, linear motors orthe like, or by resiliently supporting the “long” Y-leg, said resilientsupport being compressed when the pairs are being formed and applyingthus a resetting force to the fixed container. Preferably, the resilientsupports of opposed holding devices are provided such that they have thesame resilience or spring constants. Through the use of linearlydisplaceable holding devices, the range of conveyable containercross-sections can be extended still further. The linearly displaceableholding device additionally offers the possibility of monitoring thepenetration depth of the holding devices. If the penetration depthexceeds the tolerance to be expected, it can be assumed that a containeris fractured or that a bottle whose diameter is not large enough hasentered the machine. In both cases, an emergency stop can be triggeredimmediately, which will bring the machine to a standstill preferablywithin less than 1 sec.

According to another further development, the holding devices may bepivotable. The pivotability is here given relative to an axis parallelto the longitudinal axis of the cylindrical containers to be conveyed.The angular elements of the clamps may e.g. be pivotably supported onthe “long” Y-legs of the clamps, and a resetting element, in particulara resilient resetting element, may be provided, which resets the clampsin the empty condition to a starting position for picking up acontainer. The starting position may e.g. be a position at which one ofthe legs of the angular element defines a straight line with the “long”Y-leg. The clamps may additionally be provided with one or a pluralityof locking devices that limit the pivotability of the angular elementsto a predetermined angular area. By displacing the pair-formingconveying units relative to one another, as will be described in moredetail hereinafter, a rotation of the conveyed containers can be causedby pivoting the holding device, said rotation positioning a containersidewall area which still is to be inspected such that it can beinspected by a sidewall inspection unit arranged on the discharge side.

According to the present invention, the first and second conveyor tracksmay comprise, at least in the area of the conveying route of thethroughput station, an individual drive for moving the conveying unitsindividually and independently as well as a guide element, in particulara guide rail. In the present context, an individual drive is a drivewhich allows the conveying units to be moved with individualdisplacement-time profiles, i.e. individually and independently of oneanother. For guiding the conveying units along the respective conveyortrack, the conveyor track according to the present further developmentcomprises a guide element, e.g. in the form of a guide rail and/or aguide channel. Accordingly, the conveying units may comprise acomplementary guide channel, a complementary guide element, e.g. a guidepin, and/or one or a plurality of suitably arranged guide rollersrunning, e.g. by means of a wheel flange, on the guide rail of theconveyor track. A plurality of alternative embodiments, making e.g. useof friction bearings, is here imaginable. By providing a guide rail onthe conveyor track, the conveying units can be guided along the conveyortrack with low friction. In addition, the conveyor track may be providedwith a running surface on which respective support elements, e.g.support rollers, can roll or slide. Furthermore, the conveyor track maycomprise at least one sensor for determining the position of theconveying elements along the conveyor track. In particular, a regularand periodic arrangement of sensors along at least a subsection of theconveyor track will allow to determine the position of a conveying uniton this subsection of the conveyor track. The sensor may here beconfigured as an optical sensor, an electrical sensor, anelectromagnetic sensor or a mechanical sensor.

Tracking can especially be carried out via a control electronics for theconveying units. The respective open-loop and/or closed-loop controlunit may, on the one hand, predetermine the target positions for theconveying units and, on the other hand, it may also determine and reportthe actual positions. The positions of the conveying units can be storedin a storage unit of the open-loop and/or closed-loop control unit.Hence, additional tracking via distance sensors or trigger lightbarriers can be dispensed with to a very large extent.

According to the present invention, the conveyor track and the conveyingunits are configured such that the conveying units can be guidedindividually along the conveyor track. This means that each of theconveying units comprises at least one reaction element, which, by meansof electromagnetic interaction with interaction elements arranged alongthe conveyor track, has applied thereto a force through which theconveying unit can be accelerated and thus moved. By accuratelycontrolling the reaction element of a specific conveying unit and/or oneor a plurality of interaction elements in a limited area of the conveyortrack, this application of force can be limited to a specific conveyingunit, whereby the conveying unit can be conducted individually andindependently of other conveying units along the conveyor track.

According to a further development, the individual drive may be a linearmotor drive, the conveying units being here configured as carriages,runners, pucks, shuttles or the like, which are movable individually andindependently of one another via magnetic interaction with the linearmotor drive, and the conveyor arrangement comprising additionally anopen-loop and/or closed-loop control unit, which is configured to movethe conveying units from a pick-up site for the containers at the feedconveying device to a discharge site for the containers at the dischargeconveying device.

Conveying systems having a linear motor drive are well known in theprior art. All conveying systems with a linear motor drive have incommon that conveying elements or conveying units, which are speciallyconfigured for this purpose, are moved along one or a plurality of guiderails through magnetic interaction with the linear stator(s) or linearmotor strings of one or a plurality of linear motors.

If a linear motor drive is used as an individual drive, the conveyingunits and at least the part of the respective conveyor track along theconveying route may be configured such that the conveying units can bemoved in the area of the conveying route by means of a magnetic force,preferably in interaction with the conveyor track. The respective partof the conveyor track may especially be equipped with a magnetic lineardrive, e.g. in the form of a synchronous or asynchronous linear motor.To this end, the respective section of the conveyor track is equippedwith a plurality of electrical coils in the form of individuallycontrollable electromagnets. In order to create a magnetic interactionbetween the conveying units and the individually controllableelectromagnets of the conveyor track, the conveying unit may be equippedwith one or a plurality of permanent magnets or non-switchingelectromagnets or ferrite cores.

According to an embodiment, the conveying unit may be configured as apassive conveying unit moved by interaction with the alternatingelectromagnetic fields generated by the individually controllableelectromagnets of the conveyor track. The at least one permanent magnetor non-switching electromagnet or ferrite core of the conveying unitthus defines the above-mentioned reaction element, whereas theindividually controllable electromagnets of the conveyor track definethe above-mentioned interaction elements. If passive conveying units areused, the conveyor track has preferably arranged thereat a localizingunit so as to detect the position of at least one conveying unit and,preferably, of all conveying units and report it to a control of theelectromagnets of the conveyor track. The localizing unit may especiallybe realized by the above-described sensors. The strength of the currentthrough the electrical coils of the conveyor track may automatically beadapted by the control, depending on a power demand of the conveyingunit to be moved. By individually controlling the strength of thecurrent flowing through individual coils of the conveyor track, theconveying unit can additionally be accelerated, decelerated or moved ata predetermined constant speed.

According to an alternative embodiment, the conveying unit is, as anactive conveying unit, provided with electrical coils which are capableof applying the alternating magnetic fields required for driving.Accordingly, the respective section of the conveyor track is providedwith permanent magnets or non-switching electromagnets. The electricenergy required for driving as well as the signals required for thepurpose of control may here be transmitted to the individual conveyingunits via transmission by induction. Hence, the control may locatedoff-center on the individual conveying units or it may be accommodatedcentrally in a separate control unit. Alternatively, the necessaryelectric energy may also be transmitted to the conveying units via aline arranged along the conveyor track. In addition, a combination ofthe conveying unit configured as an active conveying unit with aconveyor track comprising individually controllable electromagnets isimaginable.

For the use of a linear motor drive, the respective conveyor track maycomprise one or a plurality of linear motor strings, which areconfigured as linear stators of linear motors, in particular ofsynchronous linear motors. According to an alternative embodiment, thelinear motor strings may also be configured as asynchronous linearmotors, the at least one permanent magnet and/or non-switchingelectromagnet of the reaction element of the conveying unit and/or anelectrically conductive element of the conveying unit, e.g. in the formof a metallic plate to which the permanent magnet and/or thenon-switching electromagnet is/are attached, serving here as electricconductors for the induction through the asynchronous linear motors.

In addition to the above-described part of the conveyor track within thethroughput station, said conveyor track part being configured as amagnetic track, the conveyor track may additionally comprise, outside ofthe throughput station, at least one subsection, e.g. a feedback track,along which the conveying unit can be moved with a constant speed. Tothis end, the subsection may comprise a drive unit in the form of aconveyor belt, a conveyor chain or the like. By combining a conveyingroute having a magnetic drive within the throughput station and afeedback track with a mechanical drive, the installation costs of theconveyor arrangement in its entirety can be reduced.

According to a further development, the conveying unit may be supportedon the conveyor track in a fully magnetic manner, or in a partlymagnetic and partly mechanical manner, or in a fully mechanical manner.In the case of a fully magnetic support, the above-described part of theconveyor track is configured as a magnetic levitation system, electricalcoils causing a magnetic levitation of the conveying unit above theconveyor track being then provided in the conveyor track and/or theconveying unit. The friction between the conveying unit and the conveyortrack can thus be reduced to a minimum. In the case of a partiallymagnetic and a partially mechanical support, the conveying unit mayadditionally comprise one or a plurality of support elements, e.g. inthe form of support rollers and/or guide rollers. The additional supportelements roll along or slide along a running surface of the conveyortrack. In the case of a fully mechanical support, the conveying unit maybe supported exclusively by the above-described at least one supportelement. Additionally or alternatively, the support may also be of apneumatic nature, the conveyor track being then configured as an airlevitation system in the subsection in question. A pneumatic supportwill, just as a fully magnetic support, minimize the friction betweenthe conveying unit and the conveyor track.

Furthermore, the conveyor arrangement may comprise an open-loop and/orclosed-loop control unit, in particular a process computer, forcontrolling the at least one conveying unit. The open-loop and/orclosed-loop control unit may here be realized by a central control unitand/or by control units arranged off-center on the conveying units. Theone or the plurality of control units may be configured such that theyindividually control, through open-loop and/or closed-loop control, theelectrical coils of the conveyor track and/or of the conveying unitssuch that the conveying units of each pair of oppositely engagingconveying units are moved simultaneously along the conveyor track forconveying the container or the containers. The speed of the pairs canhere be predetermined in accordance with a given pitch of the flow ofpairs. In addition, the pairs may be accelerated or decelerated alongthe conveying route of the throughput station, depending on the demandson the part of the inspection units arranged in the area of thethroughput station. For example, the containers may be conveyed moreslowly in the area of a specific inspection unit, or they may dwelllonger in this area, if, e.g. in the case of highly absorbent glassbottles, longer exposure times should be necessary or because twopictures, with different exposure times, are to be taken at the sameposition. By means of type management, the open-loop and/or closed-loopcontrol unit can flexibly react to a product change by adapting thedisplacement-time profiles of the pairs of conveying units to the newtype of containers on the basis of the parameters stored in said typemanagement.

The individual control of the conveying units along the conveying routeadditionally allows precise picking up of one or of several containersfrom the feed conveying device, in that the holding devices of theoppositely engaging conveying units are moved towards the containers viarespective curved tracks. The position and the movement of the containerto be picked up may here be detected via a position sensor on the feedconveying device, such as a trigger light barrier and an incrementalposition encoder, and reported to the open-loop and/or closed-loopcontrol unit of the individual drive. In the case of a plurality ofcontainers, and also in the case of containers contacting one another inthe infeed of the inspection device, one container after the other istaken hold of by a pair of conveying units in this way. This worksreliably even under conditions of ram pressure. It follows that thedevice according to the present invention represents simultaneously acontainer-blocking and a container-dosing system. The use of complexelements for pressure reduction in the infeed can therefore be dispensedwith, whereby installation and maintenance costs can be saved. Inaddition, the individual control of the conveying units allows thecontainers conveyed through the throughput station to be transferredprecisely to the discharge conveying device. The conveying speed of thecontainers at the end of the conveyor track can here preferably beadapted to the continuous conveying speed of the discharge conveyingdevice. Tilting of the containers, when the latter are put down on thedischarge conveyor, can be prevented in this way.

According to another further development, the open-loop and/orclosed-loop control unit may additionally be configured to move theconveying units of the first plurality of conveying units at least alongpart of the throughput station at a speed which is higher than that ofthe conveying units of the second plurality of conveying units. Thisresults in a relative displacement of the two conveying units acting ona container, whereby the carried-along container will be rotated aboutits longitudinal axis, especially if the holding devices of theconveying units are configured such that they are pivotable. Inparticular a rotation of the carried-along container by up to 90°,preferably by approximately 90°, is imaginable, provided that theholding devices are configured in a suitable manner. In combination withthe sidewall inspection units, which are referred to hereinafter andwhich are arranged on the infeed and on the discharge side, such arotation can be used for fully inspecting the sidewall of the container.The rotation of the container may especially take place, as a result ofthe respective two conveying units moving at different speeds, when thecontainer is taken over from the feed conveying device and/or when thecontainer is transferred to the discharge conveying device.

According to another further development, the inspection device mayadditionally comprise a first inspection station arranged near the feedconveying device and configured to inspect the passing containers fromthe side, and/or a second inspection station arranged near the dischargeconveying device and configured to inspect the passing containers fromthe side. The inspection stations may here especially be arranged at theend or at the beginning of the feed conveying device and the dischargeconveying device, respectively. Between the two inspection stations forsidewall inspection, the containers may be rotated by means of theindividual drive as described hereinbefore, so as to allow an all-aroundcheck of the containers.

According to a special further development, the first and/or secondinspection station may comprise an optical system with a camera, saidoptical system being configured such that the side of the container tobe inspected is detected within a predetermined angular area in thecircumferential direction. For example, the whole container height maybe illuminated with an LED area light, with one or a plurality of CCDcameras taking one or a plurality of pictures of the container sidewallfrom different angles of view. For example, two pictures of the sidewallcan be taken from different angles of view via a camera and an opticalsystem comprising four mirrors, the angles of view deviating from oneanother e.g. by 90° in the circumferential direction. In the case oftransparent objects, the sidewall inspection station inspects not onlythe sidewall located between the container axis and the recordingdirection but also the sidewall located on the other side of thecontainer axis. It follows that, by detecting a respective 90° angulararea on the front and on the rear side of the container, an all-arounddetection of the sidewall can be carried out, by rotating the containerby 90° in the throughput station, with the inspection stations arrangedon the infeed and on the discharge side.

In particular, the detected angular area of the first inspection stationmay be smaller than the angular area of the second inspection station.The detected angular area of the first inspection station may e.g. be anarea between 40° and 60°, whereas the detected angular area of thesecond inspection station will accordingly be larger than 90°. Hence,also containers fed under ram pressure conditions can be inspected withrespect to their sidewalls in the feed conveying device. The opticalsystems of the first and second inspection stations, in particularpossible optical elements and mirror elements, respectively, may beautomatically adjustable so that they can be adapted to the dimensionsof a new container in the case of grade changes.

According to another further development, the inspection device mayfurther comprise a bottom inspection station in the area of thethroughput station, said bottom inspection station being configured toinspect the bottoms of the passing containers. Such a bottom inspectionstation may e.g. comprise a camera, which will take a picture of thecontainer bottom that is uniformly illuminated by an LED flash lamp. Tothis end, the bottom of the container must be freely accessible, in thatthe container is conveyed in a suspended condition, in the area of theinspection station. The sensor data or optical data recorded by theinspection stations may be transmitted to an evaluation unit, e.g. acomputing unit, of the inspection device, which will evaluate the dataautomatically so as to detect damage or contamination. The data may betransmitted in a wire-bound or in a wireless fashion.

The above-mentioned objects are also achieved by a method ofcontinuously inspecting containers, in particular bottles, said methodcomprising the following steps: successive feeding of containers to athroughput station of an inspection device, conveying the fed containersin the throughput station, inspecting the fed containers in thethroughput station and discharging the inspected containers, the fedcontainers being conveyed in the throughput station by means of aconveyor arrangement comprising an individual drive and a plurality ofconveying units movable individually and independently of one another bymeans of the individual drive.

The same variations and further developments which have been describedhereinbefore in connection with the inspection device according to thepresent invention are also applicable to the continuous inspectionmethod. In particular, the containers of the throughput station can befed by means of a feed conveying device as a flow of containers. The fedcontainers are taken up by the conveyor arrangement individually or inthe form of a pack and they are conveyed along a conveying route of thethroughput station by means of the individual drive and the plurality ofconveying units independently of one another and in an individuallycontrollable manner. Inspection of the fed containers in the throughputstation can be carried out by one or a plurality of the above-describedinspection stations.

According to a further development, the fed containers can be conveyedin the throughput station by means of oppositely engaging conveyingunits, the individual drive being a linear motor drive and the conveyingunits being configured as carriages, which are movable in a controlledmanner through magnetic interaction with the linear motor drive. Also inthis case, the above-described further developments are applicable. Inparticular, a first plurality of conveying units can be moved along afirst conveyor track of the conveyor arrangement and a second pluralityof conveying units can be moved along a second conveyor track of theconveyor arrangement such that, for taking over a container from thefeed conveying device, a pair of oppositely engaging conveying units isestablished, which is subsequently de-established for transferring thecontainer to the discharge conveying device. By means of an open-loopand/or closed-loop control unit, the respective conveying units of thepairs can be moved simultaneously along the conveying route. A rotationof the container can be caused by moving the conveying units atdifferent speeds when the container is taken over and when it istransferred or moved along part of the conveying route. An all-aroundcheck of the container sidewall can thus be executed through sidewallinspection stations arranged on the infeed and on the discharge side.

According to a special further development, the containers can be fed tothe conveyor arrangement of the throughput station in a mutuallyabutting mode, i.e. under pressure. In this case, the open-loop and/orclosed-loop control unit controls the movement of the oppositelyengaging conveying units such that a blocking and dosing function isrealized through the precise formation of pairs when the containers aretaken over. The use of complex devices for reducing the pressure in theinfeed can therefore be dispensed with.

The inspection device described needs less installation space in asystem for empties inspection, since containers can be moved into thedevice under ram pressure as well as separately of one another and sincethe pressure reduction unit is therefore no longer necessary. Making useof the individual drive, a defined distance between the containers isestablished at the discharge of the throughput station, independently ofthe infeed distance. This allows the use of sidewall inspection unitshaving a viewing angle range of more than 90° on the discharge sideand/or a discharge of the inspected containers in a segment-typedischarge process. Since the containers are held in a form-fit orforce-fit manner while passing through the throughput station, thedegree of tilting will be small so that inspection units which aresensitive in this respect can operate in the best possible way. Thedrives including torque transmission of the normally used belt stationare replaced by the linear motor drive, which can react more flexibly tograde changes. For the purpose of cleaning or servicing, the conveyingunits can be moved, individually or in common, out of the throughputstation and into a servicing station that is specially provided for thispurpose.

In addition, other than in the case of known belt drives, the routing inthe throughput station may deviate from a linear routing, since theindependent control of the conveying units will easily allow alsomovements along a curved track. The conveying route of the throughputstation can thus be configured as a 90° to 180° curve so as to reducethe length of the process route. In order to prevent a plurality ofinspection stations from mutually influencing one another in the area ofthe throughput station, said inspection stations should normally beprevented from triggering simultaneously and causing e.g. a flashillumination. Due to the possibility of moving the containers within thethroughput station by means of the individual drive such that a defineddistance is established therebetween, this can easily be excluded. Itfollows that the described devices and methods will allow simplifiedplant construction and they will render the inspection device moreflexible with respect to the container types to be inspected. Set-uptimes can thus be reduced and the use of complex elements can berendered superfluous.

Additional features and exemplary embodiments as well as advantages ofthe present invention will be explained hereinafter in more detailmaking reference to the drawings. It goes without saying that theembodiments do not exhaust the scope of the present invention. It alsogoes without saying that some or all of the features describedhereinafter may also be combined with one another in other ways.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows schematically an exemplary embodiment of an inspectiondevice according to the present invention in a top view.

FIG. 2 shows an exemplary embodiment of a conveying unit and a conveyortrack with a linear motor drive.

FIG. 3 shows schematically the rotation of a container by 90° in thedischarge of the throughput station according to the present invention.

FIG. 4 shows schematically the rotation of a container by 90° in theinfeed of the throughput station according to the present invention.

FIG. 5 shows an exemplary further development of a holding device forcontainers of different diameters according to the present invention.

FIG. 6 shows schematically the interengagement of oppositely engagingclamps of holding devices according to the present invention.

FIG. 7 shows a variation of the further development according to FIG. 1with end-mounted rollers on the clamps of the holding devices.

FIG. 8 shows an exemplary embodiment of a linearly displaceable holdingdevice with end-mounted rollers.

FIG. 9 shows schematically the rotation of a container by means of aratchet mechanism.

DETAILED DESCRIPTION

In the figures described hereinafter, like reference numerals identifylike elements. For reasons of clarity, like elements will only bedescribed when they appear for the first time. However, it goes withoutsaying that the variants and embodiments of an element described withrespect to one of the figures may also be applied to the correspondingelements in the other figures.

FIG. 1 shows a schematically an exemplary embodiment of an inspectiondevice according to the present invention in a top view. In addition toa feed conveying device 110 used for feeding containers 130 insuccession and a discharge conveying device 115 used for discharging theinspected containers 134, the inspection device shown comprises athroughput station 100 arranged between the feed conveying device andthe discharge conveying device and represented here by a broken line.According to the present invention, the throughput station 100 comprisesa conveyor arrangement with an individual drive and a plurality ofconveying units 140 a to 143 a and 140 b to 143 b, which are movable bymeans of the individual drive individually and independently of oneanother and which convey the containers along a conveying route 105 ofthe throughput station 100 from the feed conveying device to thedischarge conveying device. To this end, the conveyor arrangementcomprises a first conveyor track 120 a and a second conveyor track 120 bhaving each a plurality of conveying units 140 a to 143 a and 140 b to143 b, respectively, arranged therealong. The closed conveyor tracks 120a and 120 b shown here each consist of a subsection 122 a and 122 b,respectively, arranged along the conveying route 105 within thethroughput station 100, and of a feedback track 124 a and 124 b,respectively, along which the unladen conveying units are returned forpicking up a new container at the pick-up site A.

The conveyor tracks are here arranged relative to one another andrelative to the feed conveying device 110 and the discharge conveyingdevice 115 such that, in the area of the throughput station, pairs ofoppositely engaging conveying units for the containers can be formed,each of said pairs comprising a conveying unit of the first plurality ofconveying units and a conveying unit of the second plurality ofconveying units. To this end, the conveyor tracks comprise curved piecesin the area of the pick-up site A, the conveying units 140 a and 140 bmoved along these curved pieces approaching one another until theirY-shaped holding devices receive between them a container 131 from theflow of containers 130 of the feed conveying device 110 in a form-fit orin a force-fit manner. Due to the special shape of the holding devices,this precise picking up of a single container 131 can reliably becarried out, even if the containers 130 are fed under pressure, i.e. ina mutually abutting mode. The container 131 fixed between the holdingdevices of the oppositely engaging conveying units can here be liftedfrom the feed conveying device 110 so that, while the container is beingconveyed along the conveying route 105, the bottom area as well as theoutlet area of the conveyed container are freely accessible.

According to the further development shown here, the first and secondconveyor tracks 122 a and 122 b are arranged parallel to one anotheralong the conveying route 105, so that, during the entire conveyancealong the conveying route, the conveyed containers 131 to 133 arereliably held and conveyed by the pairs defined. Exemplarily, a bottominspection station 150 is schematically shown at the conveying route 105shown here, said bottom inspection station 150 recording, e.g. by meansof a CCD camera, an optical picture of the bottom of the container 132illuminated by an LED flash lamp. The data of this inspection stationcan be transmitted to the processing unit 180, which is hereschematically shown, for further processing. The processing unit 180evaluates the data automatically, so as to detect e.g. damage of thecontainer bottom. It goes without saying that additional inspectionunits, which are not shown here, may be arranged in the area of thethroughput station 100 for inspecting the conveyed containers.

At the end of the conveying route 105 of the throughput station 100, thepairs of conveying units 142 a and 142 b are de-established at adischarge site B, e.g. by diverging curved pieces of the conveyor tracks120 a and 120 b, so that the carried-along container 133 is transferredto the discharge conveying device 115. Since the conveying units aremoved along the conveyor tracks 122 a and 122 b individually andindependently of one another by means of an individual drive accordingto the present invention, the containers conveyed in the throughputstation 100 can be conveyed, in a particular in a precise manner and ata desired distance from one another. This also allows to adjust adesired pitch d of the outgoing flow of containers 134 after theinspected containers have been transferred to the discharge conveyingdevice 115. This arrangement can be used in a particularly advantageousmanner, since this system allows to use also discharge systems that arenot able to discharge closely packed containers in an upright condition.Also for closely packed containers, the discharge rate is positivelyinfluenced by purposefully creating a distance. In order to avoid here aback-up situation, the speed of the discharge conveyor may be increasedby the magnitude of the distance from one container to the next in theinfeed plus a desired gap.

It follows that the inspection device shown allows the containers 130 tobe fed under pressure as well as to move the conveyed containers apartto a desired discharge pitch d. The movement of the conveying unitsalong the conveying route 105 takes here place with an individualdisplacement-time profile via an open-loop and/or closed-loop controlunit of the conveyor arrangement, which may e.g. be configured as partof the processing unit 180. According to the further development shownhere, the conveyor tracks 120 a and 120 b are provided throughout theirlength with an individual drive, e.g. in the form of the linear motordrive shown in FIG. 2, so that the conveying units can also be returnedalong the feedback tracks 124 a and 124 b with an individualdisplacement-time profile. In particular, the conveying units can beguided along the feedback tracks at a higher speed so as to keep thetotal number of necessary conveying units small. Moreover, the feedbacktracks 124 a and 124 b can be used for buffering conveying units. As hasalready been described, also feedback tracks having a continuous drive,e.g. in the form of a belt conveyor or a conveyor chain, may be providedfor reducing the costs of installation and operation.

According to the further development shown here, the inspection deviceadditionally comprises a first sidewall inspection station 160 arrangedon the infeed side at the feed conveying device 110 and used forinspecting a first angular area of the sidewalls of incoming containers130, and a second sidewall inspection station 170 arranged at thedischarge conveying device 115 and used for inspecting a second angulararea of the sidewalls of outgoing containers 134. As indicated in FIG. 1by the container dividing line, the containers may be rotated by e.g.90° while they are being conveyed, so that the first and second sidewallinspection stations 160 and 170 will inspect respective other subareasof the sidewalls of the containers so as to allow an all-around check ofthe container sidewall. According to the schematic further developmentshown here, the containers 133 are rotated by 90° when they aretransferred to the discharge conveying device 115. Since the incomingcontainers 130 according to this further development are conveyed in amutually abutting mode, the angular area detected by the first sidewallinspection station 160 is normally smaller than 90°. Since the flow ofcontainers is, however, moved apart to a pitch d in the dischargeconveying device 115, the second sidewall inspection station 170 will beable to detect also an angular area larger than 90°, so that, incombination with the area detected by the first sidewall inspectionstation 160, a complete detection of the sidewalls of the conveyedcontainers will be obtained. Also in this case, the acquired sensorand/or image data of the sidewall inspection stations 160 and 170 can betransmitted to the processing unit 180 for automatic further processing.The variant shown here, in the case of which the conveyed containers arerotated during transfer to the discharge conveying device 115, onlyrepresents one possible variant. Alternatively, the containers may berotated when they are taken over from the feed conveying device 110 orthey may be rotated by a respective smaller angle when they are takenover as well as when they are transferred. Furthermore, an at leastpartial rotation of the containers by an angle smaller than 90° can alsobe accomplished by moving the conveying units 141 a and 141 b of eachpair at different speeds. Two special further developments for rotatingthe conveyed containers will be explained hereinafter in detail inconnection with FIGS. 3 and 4.

FIG. 2 shows an exemplary embodiment of a conveying unit and a conveyortrack in cases where a linear motor drive is used for individuallymoving the conveying unit. The present invention is, however, notlimited to the special embodiment of the conveying unit shown here, butit is applicable to any kind of individually movable conveying units aslong as oppositely engaging conveying units are able to move thecontainers along the conveying route in a form-fit or in a force-fitmanner. The conveying unit 200 shown here can be guided along theconveyor track by means of a guide rail 240. According to this specialembodiment, the conveying unit is supported on the guide rail 240 by afriction bearing 220. The figure additionally shows a holding device 210by means of which the conveying unit will be able to take hold of andconvey the containers.

According to the exemplary embodiment shown here, the holding device 210is depicted in the form of an upsilon which is open towards thecontainer and which has an opening angle a between the two “short”Y-legs 210-1 and 210-2. The “long” leg 210-3 of the Y is fixed via aholder 260 to the conveying unit 200 in a linearly displaceable manner,a gear 270, which is driven by a servomotor (not shown), meshing with atoothed rack of the “long” Y-leg 210-3. As regards the lateraldisplacement of the holding device 210, a large number of alternativeembodiments is imaginable. For example, the holding device 210 may befixed to the conveying unit 200 by means of a resilient element suchthat, for receiving the container to be conveyed, the clamp defined bythe Y-legs 210-1 and 210-2 is linearly displaceable relative to thefriction bearing 220 by compressing this resilient element.

The sides of the Y-legs 210-1 and 210-2 of the clamp facing thecontainer may be coated with an adherent layer so as to guaranteereliable holding of the container when the latter is conveyed in asuspended condition. Alternatively, the whole legs 210-1 and 210-2 mayconsist of this material having a sufficiently high static friction,and, in particular, the Y-legs may be made of a resiliently deformablematerial. In the latter case, the angle between the two Y-legs may beadapted to be changed, by deforming the resilient material, such thatthe clamp will be able to reliably receive therein a large number ofdifferent container types with different cross-sectional diameters.

According to the special further development shown here, the Y-shapedclamp 210 is additionally supported on the conveying unit 200 such thatit is pivotable via a pivot bearing 280. Resetting elements, which arehere not shown and which are used for resetting the unladen clamp 210 toa predetermined starting position, may be provided. Moreover, a pivotalmovement of the clamp may be limited to a desired angular area bylocking devices, which are here not shown.

The drive of the passive conveying unit shown here is effected bymagnetic interaction between the reaction element 230 of the conveyingunit and a plurality of electrical coils 250 along the conveyor track.The electrical coils 250 can be controlled individually by means of anopen-loop and/or closed-loop control unit (not shown) and, aselectromagnets, they can individually undergo a polarity reversal. Dueto interaction of the magnetic fields of the electromagnets with thehere shown permanent magnet of the conveying unit, the conveying unit issubjected to an action of force which, on the basis of a suitablecontrol of the electromagnets 250, results in an acceleration, adeceleration or a constant movement of the conveying unit along theguide rail 240. The here shown reaction element 230 of the conveyingunit consists of three permanent magnets arranged in an alternating modeand perpendicular to the guide rail, the width of the central permanentmagnet corresponding approximately to the distance between twoneighboring electrical coils of the conveyor track and the width of eachof the outer permanent magnets corresponding approximately to half thedistance between the neighboring electrical coils. It follows that, inthe case of an alternating polarization of neighboring electromagnets inthe conveyor track, a maximum force can act on the reaction elementalong the guide rail. By individually controlling the electromagnets250, the conveying unit 200 can be moved along the guide rail 240 at thespeed V predetermined by an open-loop and/or closed-loop control unit ofthe conveyor arrangement. In particular, a large number of conveyingunits can be moved along the guide rails in a controlled manner suchthat an adaptation of the container pitch along the conveying route willbe effected (see above).

FIG. 3 shows schematically the rotation of a container by 90° in thedischarge of the throughput station according to the present invention.In said figure, the conveyed container 333 is shown in four differentphases a) to d) of this rotation. It goes without saying that thefurther development shown is only of an illustrative nature and does notlimit the scope of the present invention. As regards the conveyingunits, only the clamps 312 thereof are shown in said figure, said clamps312 being supported on the conveying units via pivot bearings 280.

On the basis of the pivot bearings 280, the clamps 312 can be pivoted bymoving the pair-forming conveying units at different speeds, asindicated in the present case by the different lengths of the motionarrows. By moving the two conveying units of a pair at different speedsalong their conveyor tracks, the clamps 312 of said conveying units moveincreasingly away from one another, thus causing a rotation of thecarried-along container 333, as indicated here by the longitudinal line.

At the beginning of this development (cf. subfigure a)), the opposedconveying units of the pair move at the same speed, so that the fixedcontainer 333 is symmetrically held between the opposed clamps 312. Incomparison with the situation in subfigure a), the lower conveying unithas been accelerated in subfigure b), so that the associated clamp 312will move ahead of the clamp of the upper conveying unit. This has theeffect that both clamps 312 are simultaneously pivoted about therespective pivot bearing 280, whereby the carried-along container 333 ispartially rotated. In subfigure c), the two conveying units have alreadybeen moved away from one another to such an extent that thecarried-along container 333 is no longer in contact with a respectiveone of the legs of the clamps 312. Due to the static friction betweenthe container 333 and the other leg, the container will, during theincreasing degree of shearing of the two clamps, roll on the legs suchthat the initial rotation of the container will be continued until arotation by approximately 90° has been reached.

Subfigure d) shows the situation after the end of the rotation of thecontainer 334. The latter has already been put down on the dischargeconveying device 115. Due to the resetting elements, which are notshown, the clamps 312 are pivoted back to their original position whenthe container 334 has been put down, so that the conveying units areprepared to pick up another container. The container 334, which has nowbeen rotated, can be inspected in a downstream sidewall inspectionstation with respect to the hitherto unexamined sidewall area.

FIG. 4 shows schematically an alternative further development in thecase of which a container is rotated by 90° in the infeed of thethroughput station. According to the further development shown here, theincoming containers 430 are fed under pressure, i.e. in a mutuallyabutting mode, by means of the feed conveying device 110. Also accordingto this further development, each of the conveying units 440 a to 443 aand 440 b to 443 b, respectively, is provided with a clamp 412 which issupported on the respective conveying unit by means of a pivot bearing480. In addition, the holding devices of the conveying units shown hereare supported by means of a resilient element 475, so that the clamp 412is linearly displaceable with respect to the support of the conveyingunit on the respective conveyor track 422 a or 422 b.

Other than in FIG. 3, the initial position of the clamps 412 of theholding devices shown in FIG. 4 is, e.g. by a resetting element that isnot shown, predetermined such that a Y-leg of the clamp is aligned alonga straight line with the linearly displaceable leg of the holdingdevice. The clamps 412 of opposed conveying units 440 a and 440 b areagain arranged relative to one another such that their openings arelocated in opposed relationship with one another. According to thefurther development shown here, the Y-legs of the clamps 412 areexemplarily configured with right angles and rigidly, so that, as shownin FIG. 5, a large number of containers with different containerdiameters can be held reliably. The Y-leg arranged in linear alignmentwith the “long” leg of the holding device of the conveying unit 440 acan, provided that the Y-leg is configured in a suitable manner and thatthe curved piece of the conveyor track 422 a is arranged in a suitablemanner, be inserted into the infeed flow between the container to bepicked up and the downstream container in said flow. Simultaneously, theconveying unit 440 b approaches the feed conveying device 110 along arespective curved piece of the conveyor track 422 b such that the Y-leg412 arranged upstream of the container to be picked up will serve as ablocking means preventing the container from slipping out of thetransfer site. A single container can thus be accurately taken over fromthe flow of containers 430, and a dosing and blocking function issimultaneously fulfilled by the formation of the pair of conveying units440 a and 440 b.

The conveying units 441 a and 441 b are moved towards each other to suchan extent that, according to this further development, both Y-legs ofthe respective clamp 412 are moved into contact with the container 431to be held. In the course of this process, the resilient elements 475may be compressed at least partially so that the Y-legs of the clamps412 abutting in a direction laterally to the conveying direction will bepressed with sufficient force against the container wall of thecontainer 431. The dimensions of the Y-legs in the longitudinaldirection of the containers can here be chosen such that the staticfriction prevailing between the clamps 412 and the outer surface of thecontainer will be sufficiently high for reliably holding the conveyedcontainer 431. Also when the container is rotated while it is taken overfrom the feed conveying device 110, this rotation will take place bymoving the pair-forming conveying units 442 a and 442 b at differentspeeds, as indicated by the arrows of different lengths in the presentfigure. In this case the conveying unit 442 a is moved by means of theopen-loop and/or closed-loop control unit at a speed that is higher thanthat of the conveying unit 442 b so that the carried-along container 432will be rotated clockwise, as indicated by the longitudinal line of saidcontainer. In the course of this process, the clamps 412 are pivotedabout the pivot bearing 480 such that both Y-legs of the clamps willalways remain in contact with the container. In view of the fact thatthis, however, leads to a change in the distance of the respective pivotbearing 480 from the conveying units 442 a and 440 b, respectively, theresilient elements 475 will be compressed by these changes in distance.

By continuing to move the conveying unit 443 a at a higher speed thanthe conveying unit 443 b, this rotation of the container 433 willcontinue until a rotation of about 90° has taken place. In thissituation, the position of the clamps 412 has changed by 90° relative totheir initial position, both Y-legs of each clamp being still in contactwith the outer surface of the container. For further conveyance of thecontainer 433, the pair-forming conveying units 443 a and 443 b can thenbe moved on at the same speed. After transfer of the carried-alongcontainer to the discharge conveying device, the respective clamps 412can be returned to their original positions by a suitably providedresetting element, so as to pick up a further container of the infeedflow 430. A large number of alternative further developments foraccurately picking up and reliably conveying a container as well as forrotating the container by moving, at different speeds, the conveyingunits of the pair holding the container is imaginable.

FIG. 5 shows an exemplary further development of a holding device forcontainers having different diameters according to the presentinvention. As has already been the case in FIG. 4, also the Y-legs ofthe clamp 512 according to this further development are provided atright angles and are supported at their point of intersection via apivot bearing 580 on a part of the holding device, which is linearlydisplaceable by means of a resilient element 575, on the hereschematically shown bearing 540 of the conveying unit. Representatively,three exemplary container cross-sections 530 to 532 are shown in thisfigure by a broken line, both Y-legs of the clamp 512 being always incontact with the outer surface of the container. For containers 530whose diameter is smaller than the length of the Y-legs of the clamp512, the oppositely engaging clamps of the respective conveying unitscan be arranged in an offset mode along the pivot axis of the pivotbearing 580 and, consequently, along the longitudinal axis of thecontainer, as shown e.g. in FIG. 6.

According to the further development shown here, the holding device isadditionally provided with a resilient resetting element 590 whichreturns the clamp 512 to the here shown starting position in the unladencondition. In addition, a locking device 595, e.g. in the form of alocking pin, may be provided, which limits the pivotal movement of theclamp 512 to a desired angular area. The carried-along container canthus be prevented from slipping out of the oppositely engaging clamps ofthe pair of conveying units.

FIG. 6 shows schematically the interengagment of oppositely engagingclamps of holding devices according to a special further development.According to this exemplary further development, the holding devices ofthe oppositely engaging conveying units are provided with a plurality ofclamps 612 a and 612 b, which are arranged in an offset mode along thepivot axis and which interengage in a comblike manner in thenon-limiting further development shown here. For example, the holdingdevice of the conveying units of the first plurality may comprise threeclamps 612 a offset along the longitudinal axis of the container andjointly supported via a pivot bearing 680 a on the “long” leg 610 a ofthe holding device. In a corresponding manner, the holding device of theconveying unit of the second plurality of conveying units may beprovided with two clamps 612 b offset along the longitudinal axis of thecontainer and supported via a corresponding pivot bearing 680 b on the“long” leg 610 b of the holding device. In the embodiment shown, theclamps of the two holding devices interengage, without impeding oneanother, due to their length which is large in comparison with thediameter of the container 630. Due to the comblike interengagement ofthe clamps, the container is here reliably prevented from tilting whileit is being conveyed along the throughput station.

FIG. 6 shows exemplarily a bottle 630, which is held in a suspendedcondition between the clamps 612 a and 612 b, so that the containerbottom 632 and the outlet area 631 of the bottle are simultaneouslyfreely accessible. Hence, the whole bottle 630 can be inspected alongits longitudinal direction by means of suitable inspection units, sothat both the bottom area 632 and the outlet area 631 can be inspectedfor damage and contamination.

FIG. 7 shows a variation of the further development according to FIG. 1with end-mounted rollers on the clamps of the holding devices. Theinspection device shown corresponds substantially to the furtherdevelopment according to FIG. 1 and will therefore not be described oncemore. In addition, the holding devices of the conveying units 640 a to643 a and 640 b to 643 b according to the further development of FIG. 7are formed with end-mounted rollers provided on the clamps and holdingthe conveyed containers in a form-fit manner such that the latter areprevented from slipping out on the one hand and adapted to be rotatedabout their longitudinal axis on the other. The rollers may especiallyconsist of a material exhibiting a sufficiently high static friction orthey may be coated with such a material, so as to avoid slipping out ofthe conveyed containers. For rotating the containers fixed between therollers of opposed holding devices, two friction belts 655 a and 655 bare provided in the non-limiting further development shown here, saidfriction belts being arranged on either side of the conveying route 105such that the rollers of the conveying units 641 a and 641 b can bebrought into mechanical engagement therewith. Due to the movement of thecontainer, which is held by the conveying units, relative to thefriction belts and/or a friction belt rotation that is driven in acontrolled manner, the containers can be rotated by a desired angleindirectly via the rollers of the holding devices. The open-loop and/orclosed-loop control unit 180 can drive the friction belts 655 a and 655b such that containers of different diameters will be rotated by thedesired angle. It goes without saying that also further developmentscomprising only one friction belt 655 a or 655 b, which engages from oneside, are possible. Furthermore, the friction belts 655 a and 655 b maybe configured such that they can be displaced to the side so as to allowa grade change to containers having different diameters.

FIG. 8 shows an exemplary embodiment of a linearly displaceable holdingdevice with end-mounted rollers. According to this embodiment, theconveying unit 840 comprises a “long” leg 810-3 which is displaceablerelative to the position of the conveying unit on the conveyor track 822b and on which the two “short” legs 810-1 and 810-2 of the Y-shapedholding device are supported in an angularly displaceable manner. Inaddition, the two “short” legs are connected to one another by aresilient element 811 in such a way that the legs can only be movedapart against the tension of this resilient element. Furthermore, the“short” legs 810-1 and 810-2 have arranged thereon the above-mentionedend-mounted rollers 813, which are adapted to be brought into contactwith the surface of the container 133. The whole holding device can bemoved up to the container, e.g. via the control curve 826 b shown andthe roller 814 running therein, such that the rollers will be pressedagainst the curved surface of the container and will thus be pushedapart. Provided that the rollers are suitably configured, e.g. rubbercoated, it can thus be guaranteed that the conveyed containers will beheld reliably. According to the further development shown here, thecontrol curve 826 b is configured such that the container 133 will bereleased towards the right, e.g. for discharge through a dischargeconveying device.

FIG. 9 shows schematically how a container is rotated by means of aratchet mechanism. The figure shows the rotation of the container by apredetermined (small) angle in three phases. A basic prerequisite forthe use of the ratchet mechanism is that the end-mounted rollers 913 aand/or the end-mounted rollers 913 b of the holding devices of theoppositely engaging conveying units 940 a and 940 b are configured suchthat they will lock in one direction of rotation and rotate freely inthe other direction of rotation. According to the further developmentshown here, the container is rotated when the conveying units are movedtowards one another, with at least the rollers 913 b locking in aclockwise direction. If, however, the conveying unit 940 a is used as anactive conveying unit for rotating the container, at least the rollers913 a will lock in an anticlockwise direction. Hence, the container canalso be rotated when the conveying units are moved away from each other.In this case, the rollers 913 a lock in a clockwise direction or therollers 913 b lock in an anticlockwise direction, depending on whetherthe conveying unit 940 a or the conveying unit 940 b is actively usedfor rotating the container.

According to the variant shown in FIG. 9, the conveying unit 940 b isactively used for rotating the container 931. At the starting positionshown on the left, the two conveying units 940 a and 940 b are arrangedin opposed relationship with one another. By moving the conveying unit941 b faster than the conveying unit 941 a, the two conveying units aremoved apart, as shown in the middle of the figure. The rollers 913 b,which rotate freely in an anticlockwise direction, roll on the surfaceof the container 932, which cannot participate in this rotating movementdue to the fact that the rollers 913 a lock in a clockwise direction.Only when the conveying units 942 a and 942 b are again moved towardseach other, as shown on the right-hand side of the figure, the frictionbetween the now locked rollers 913 b and the surface of the container933 will have the effect that also the container will be rotated. Inthis phase, the rollers 913 a, which freely rotate in an anticlockwisedirection, roll on the surface of the container. In order to achieve alarger angle of rotation, this process can be repeated until the angleof rotation has been accomplished. The arrows shown in the figure onlyshow the relative movement of the conveying units, which may, of course,have superimposed thereon a general movement for conveying thecontainer.

In order to be able to realize the ratchet mechanism, the holdingdevices of the conveying units are configured such that they arepivotable at least in a predetermined angular area and, optionally, suchthat they are linearly displaceable. The ratchet mechanism can thus beused for a large number of different container diameters. The relativedisplacement of the oppositely engaging conveying units can here beeffected by an open-loop and/or closed-loop control unit of the conveyorarrangement in accordance with the diameter of the containers to berotated.

The inspection devices described allow a reliable and individuallycontrollable guidance of containers along the conveying route of thethroughput station, so that, depending on the requirements to befulfilled and on the type of containers, a desired speed and/or adesired inspection time of the containers can be predetermined. Thus,e.g. very strongly absorbing glass bottles that need a longer exposuretime can dwell longer at the respective inspection station. In addition,the use of the individual drive allows individual containers to bepicked up accurately from an infeed flow, even if the latter is conveyedunder pressure, as well as to accurately predetermine a container pitchwhen the containers are transferred to the discharge flow, wherebycomplex devices for pressure reduction can be dispensed with in theincoming flow of containers.

1. An inspection device for continuously inspecting fed containers, inparticular bottles, comprising: a feed conveying device configured tofeed containers to the inspection device in succession, a dischargeconveying device configured to discharge the inspected containers, athroughput station for the containers, which is arranged between thefeed conveying device and the discharge conveying device, and a bottominspection station in an area of the throughput station, said bottominspection station being configured to inspect bottoms of passingcontainers, wherein the throughput station comprises a conveyorarrangement with an individual drive and a plurality of conveying units,which are movable by means of the individual drive individually andindependently of one another, the conveyor arrangement being configuredto convey the containers from the feed conveying device to the dischargeconveying device, wherein the individual drive is a linear motor drive,wherein the plurality of conveying units are configured as carriages,which are movable individually and independently of one another viamagnetic interaction with the linear motor drive, and wherein theconveyor arrangement additionally comprises an open-loop and/orclosed-loop control unit, which is configured to move the conveyingunits from a pick-up site for the containers at the feed conveyingdevice to a discharge site for the containers at the discharge conveyingdevice.
 2. The inspection device according to claim 1, furthercomprising a first inspection station arranged near the feed conveyingdevice and configured to inspect the containers from a side, and/or asecond inspection station arranged near the discharge conveying deviceand configured to inspect the containers from the side.
 3. Theinspection device according to claim 2, wherein the first and/or secondinspection stations comprises an optical system with a camera, saidoptical system being configured such that the side of the container tobe inspected is detected within a predetermined angular area.
 4. Theinspection device according to claim 3, wherein an angular areainspected by the first inspection station is smaller than an angulararea inspected by the second inspection station.
 5. The inspectiondevice according to claim 1, wherein the bottom inspection stationcomprises a camera configured to record an image of a bottom of eachcontainer passing the bottom inspection station of the containers. 6.The inspection device according to claim 5, wherein the bottominspection station further comprises a flash lamp for illuminating thebottom of each container passing the bottom inspection station of thecontainers.
 7. The inspection device according to claim 1, wherein eachof the plurality of conveying units comprises a holding device, inparticular a clamp, configured to hold at least one container.
 8. Theinspection device according to claim 7, wherein the holding device isvertically adjustable.
 9. The inspection device according to claim 7,wherein the holding device is displaceable relative to the conveyingunit.
 10. The inspection device according to claim 7, wherein theholding device is pivotable.
 11. The inspection device according toclaim 7, wherein the holding device comprises an elastomeric coating.12. A method of continuously inspecting containers, in particularbottles, comprising the following steps: successively feeding containersto a throughput station of an inspection device, conveying the fedcontainers in the throughput station, inspecting a bottom section of thefed containers in the throughput station, and discharging the inspectedcontainers, wherein the fed containers are conveyed in the throughputstation by means of a conveyor arrangement comprising an individualdrive and a plurality of conveying units movable individually andindependently of one another by means of the individual drive, whereinthe individual drive is a linear motor drive, and wherein the conveyingunits are configured as carriages, which are movable in a controlledmanner through magnetic interaction with the linear motor drive.
 13. Themethod according to claim 12, further comprising: inspecting thecontainers from a side before entering the throughput station, and/orinspecting the containers from a same or a different side after leavingthe throughput station.
 14. The method according to claim 13, furthercomprising: rotating the containers during transfer from a pick-up sitefor the containers at a feed conveying device to a discharge site forthe containers at a discharge conveying device.
 15. The method accordingto claim 14, wherein the containers are rotated at least one of duringpick-up from the feed conveying device and during transfer to thedischarge conveying device.